Radioisotopes, as radiopharmaceuticals, have come into widespread usage in hospitals and the like for diagnostic and other purposes. Once the radioactive material is manufactured it is shipped in multidose containers to the using or distributing site, such as a radio pharmacy, for later dispensing and shipment of prescribed single doses to the ultimate user. This procedure presents little problem except in the case of those isotopes such as thallium, gallium, and technitium which have relatively short half-lives. In the case of thallium-201, for example, which is used in heart imaging, the half-life is in the order of 73 hours. Thus this radioisotope while having a high value in use, i.e., heart studies, is perishable and after manufacture must be shipped quickly to the user before its strength decays below that needed for heart imaging. This necessitates, in many cases, shipment by air which is relatively expensive and does not permit the user to maintain a supply on hand for unanticipated needs. This can create unacceptable delays in performing often urgently needed diagnostic tests.
The radioactive materials could be shipped in larger quantities and stored until the user is ready for them. This presents a problem, however, since one does know how much is used of the material and how the user should be billed for such material used.